Hip fractures, wherein the femur is fractured one or more times in the area of the femur or immediately subjacent the head, are comparatively common. A great many devices have been proposed for the reduction of fractures of this type. While many of these devices have found the application and have advantages relative one to another, there remain some problems and areas of continuing concern.
Such reduction devices consist, basically, of an elongate lag screw which is threaded on one end to be threadably received in the head of the femur, and is secured to a plate such that when the lag screw is tightened, the head of the femur is forceably compressed at the fracture line to the remainder of the femur. Devices of this type, generally, are described in the U.S. Pat. Nos. 2,526,959 and 3,554,193, in which various modifications in the manner of attachment of the lag screw to the trochanteric plate have devised.
It has also been recognized that various adjustment features are important in treating certain femural fractures. In general, fastener devices with such adjustment features employ a guide sleeve which is imbedded in one bone segment, such as the upper segment of the femur, in order to receive and adjustably hold one end of an axially elongated shaft, e.g. a lag screw, which extends through both fractured bone segments, with the end of the shaft opposite the guide sleeve being provided with structure for securing the shaft to the head of the femur. Because of absorption occurring during the healing process, it has been necessary, in some instances, to accommodate a certain amount of telescoping movement between the shaft and the guide sleeve. Clasping devices within this class generally are described in the U.S. Pat. Nos. 3,996,931 and 4,095,591, both of which also refer to other patents which have related disclosures.
Functionally, some of these devices perform quite satisfactorily for many fractures of the femur but are extremely difficult for the surgeon to properly implant. It is, therefore, of great importance to provide a fixation device which is not only functional in providing the necessary stability and guidance in the reduction of the fracture, but can be efficiently, accurately and quickly implanted by the surgeon. A principal feature of the invention is to provide a device which accomplishes the desired heretofore achieved result.